I was unbolting the stock cast iron manifolds on my 92 305 TA and discovered something I've not seen in 30-something years of working on cars. There was NO gasket between the manifolds & the heads! I checked in my Official Pontiac shop manual and it does not show gaskets on the exhaust manifolds either. I wonder, how did this EVER seal? and if I decide to re-use the manifolds, should I reassemble it the same way?

TT

 

Yep the factory manifolds didnt use gaskets. My brothers 95 Silverado was the same way. I thought someone had taken them off at some point so I put gaskets on it and it leaked. So long as the manifold isnt warped, they dont need them. If they are warped, then thats a good reason for headers.

 

lol, I would use them just to save the trouble, or atleast some red rtv.

My dad said he had never installed a set. Last year we put an old 350 in a 69 chevy when we pulled the old 307. We didnt put any back on, he said it would be fine. Hasnt leaked yet.

 

 

I know I was quite shocked when I found this out myself also

 

hmm... when I installed my headers, not even two weeks I had an exhaust leak, I had to buy copper gaskets, never again have I had an exhaust leak... so this not using gaskets, does it also apply to headers?

 

no. just factory cast iron manifolds.

 

I'm kinda leery about not putting in gaskets, even though it came without them. I'm considering using a set of Mr Gasket copper gaskets just for my own peace of mind. What do you all think?

TT

 

I see nothing wrong with it, worst that can happen is your car rejects them and you have to pull the manifolds off and take the gaskets off...

 

Yeah, true..... But getting the manifolds off was a PITA. I think i'm gonna go ahead and do the gaskets anyway.

 

well with this new found knowledge that they didn't come with gaskets from the factory, then I would too only install them with copper gaskets, that's if I were to install any in the first place...

 

Point made.

TT

 

Most OEMs didn't use a gasket at the mechanical fuel pump either.
There was no point as the best seal is direct metal to metal.

 

Chrysler 360's and 318's also don't use exhaust manifold gaskets.